Isolation, Identification, and Immunomodulatory Mechanism of Peptides from Lepidium meyenii (Maca) Protein Hydrolysate

Abstract

Maca is a protein-enriched edible plant with immunomodulatory activity. However, the role of proteins in the immunomodulatory activity of maca is unclear. In this study, peptide products of maca proteins obtained through in vitro gastrointestinal digestion were isolated and purified, and the immunomodulatory activities of these peptides were assessed in macrophages (RAW 264.7 cells). The results show that the maca protein hydrolysate enhanced the phagocytic capacity and NO, TNF-α, and IL-6 secretion of RAW 264.7 cells. Forty-five peptides from known proteins of maca or the cruciferous family were identified by ultraperformance liquid chromatography–tandem mass spectrometry in the hydrolysate, and the peptide RNPFLP exhibited the strongest immunomodulatory activity. Antibody blocking, siRNA, pathway inhibitors, and western blot assays showed that RNPFLP-activated RAW 264.7 cells through the NF-κB and MAPK signaling pathways mediated by TLR2 and TLR4 receptors. An analysis of the structure–activity relationship showed that the N9-H60 active site in arginine plays an important role in the immunomodulatory activity of RNPFLP. This study provides a new understanding of the immunomodulatory activity of maca.

Anti-Inflammation and Anti-Melanogenic Effects of Maca Root Extracts Fermented Using Lactobacillus Strains

“…Some maca root components may play an immunoregulatory role by releasing pro-inflammatory cytokines and producing NO [ 42 , 43 ]. However, these pro-inflammatory cytokines contribute to the exacerbation of allergic asthma [ 61 ].…”

“…Maca effectively controls sexual dysfunction, memory enhancement, skin protection, and also has neuroprotective, antidepressant, and anticancer properties [ 34 , 39 , 40 , 41 ]. In addition, polysaccharides, or peptides, from maca regulate immunomodulatory mechanisms by enhancing the secretion of nitric oxide (NO), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6) in macrophages [ 42 , 43 ]. There are few studies on the effects of maca on the skin.…”

Phenolic Acid–Amino Acid Adducts Exert Distinct Immunomodulatory Effects in Macrophages Compared to Parent Phenolic Acids

“…6,7 The health-promoting effects of the dietary polyphenols are exerted by directly interacting with and altering the activity of immune cells such as macrophages. 8 As one of the most important innate immune cells at tissue barrier surfaces, macrophages constitute a critical link between innate and adaptive immunity, 9 performing functions such as elimination and killing of pathogens through oxygen-dependent and oxygen-independent pathways, production of pro-inflammatory cytokines, and presentation of antigens. 10 The activation of macrophages is mediated by the pattern recognition receptors, which usually mediate the activation of signaling pathways (e.g., active mitogen-activated protein kinase, MAPK, pathway), 8 leading to the production of reactive oxygen species (ROS), prostaglandin E 2 (PGE 2 ), and pro-inflammatory cytokines, such as interleukins (ILs) and tumor necrosis factors (TNFs).…”

“…The health-promoting effects of the dietary polyphenols are exerted by directly interacting with and altering the activity of immune cells such as macrophages . As one of the most important innate immune cells at tissue barrier surfaces, macrophages constitute a critical link between innate and adaptive immunity, performing functions such as elimination and killing of pathogens through oxygen-dependent and oxygen-independent pathways, production of pro-inflammatory cytokines, and presentation of antigens .…”

“…8 As one of the most important innate immune cells at tissue barrier surfaces, macrophages constitute a critical link between innate and adaptive immunity, 9 performing functions such as elimination and killing of pathogens through oxygen-dependent and oxygen-independent pathways, production of pro-inflammatory cytokines, and presentation of antigens. 10 The activation of macrophages is mediated by the pattern recognition receptors, which usually mediate the activation of signaling pathways (e.g., active mitogen-activated protein kinase, MAPK, pathway), 8 leading to the production of reactive oxygen species (ROS), prostaglandin E 2 (PGE 2 ), and pro-inflammatory cytokines, such as interleukins (ILs) and tumor necrosis factors (TNFs). 11 Inflammation, a complex immune response of the body modulated by an array of inflammatory mediators and cytokines that are released by activated macrophages, 12 is important for the protection against infection, but when not appropriately regulated, it can lead to chronic disease including cardiovascular diseases, type II diabetes, and neurodegenerative disorders such as Alzheimer's, Parkinson's, and Huntington's disease.…”